mcs/class/System/System.Net/WebConnectionStream.cs

   1 //
   2 // System.Net.WebConnectionStream
   3 //
   4 // Authors:
   5 //      Gonzalo Paniagua Javier (gonzalo@ximian.com)
   6 //
   7 // (C) 2003 Ximian, Inc (http://www.ximian.com)
   8 // (C) 2004 Novell, Inc (http://www.novell.com)
   9 //
  10
  11 //
  12 // Permission is hereby granted, free of charge, to any person obtaining
  13 // a copy of this software and associated documentation files (the
  14 // "Software"), to deal in the Software without restriction, including
  15 // without limitation the rights to use, copy, modify, merge, publish,
  16 // distribute, sublicense, and/or sell copies of the Software, and to
  17 // permit persons to whom the Software is furnished to do so, subject to
  18 // the following conditions:
  19 //
  20 // The above copyright notice and this permission notice shall be
  21 // included in all copies or substantial portions of the Software.
  22 //
  23 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  24 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  25 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  26 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  27 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  28 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  29 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  30 //
  31
  32 using System.IO;
  33 using System.Text;
  34 using System.Threading;
  35
  36 namespace System.Net
  37 {
  38         class WebConnectionStream : Stream
  39         {
  40                 static byte [] crlf = new byte [] { 13, 10 };
  41                 bool isRead;
  42                 WebConnection cnc;
  43                 HttpWebRequest request;
  44                 byte [] readBuffer;
  45                 int readBufferOffset;
  46                 int readBufferSize;
  47                 int contentLength;
  48                 int totalRead;
  49                 long totalWritten;
  50                 bool nextReadCalled;
  51                 int pendingReads;
  52                 int pendingWrites;
  53                 ManualResetEvent pending;
  54                 bool allowBuffering;
  55                 bool sendChunked;
  56                 MemoryStream writeBuffer;
  57                 bool requestWritten;
  58                 byte [] headers;
  59                 bool disposed;
  60                 bool headersSent;
  61                 object locker = new object ();
  62                 bool initRead;
  63                 bool read_eof;
  64                 bool complete_request_written;
  65                 int read_timeout;
  66                 int write_timeout;
  67
  68                 public WebConnectionStream (WebConnection cnc)
  69                 {
  70                         isRead = true;
  71                         pending = new ManualResetEvent (true);
  72                         this.request = cnc.Data.request;
  73                         read_timeout = request.ReadWriteTimeout;
  74                         write_timeout = read_timeout;
  75                         this.cnc = cnc;
  76                         string contentType = cnc.Data.Headers ["Transfer-Encoding"];
  77                         bool chunkedRead = (contentType != null && contentType.ToLower ().IndexOf ("chunked") != -1);
  78                         string clength = cnc.Data.Headers ["Content-Length"];
  79                         if (!chunkedRead && clength != null && clength != "") {
  80
  81                                 try {
  82                                         contentLength = Int32.Parse (clength);
  83                                         if (contentLength == 0 && !IsNtlmAuth ()) {
  84                                                 ReadAll ();
  85                                         }
  86                                 } catch {
  87                                         contentLength = Int32.MaxValue;
  88                                 }
  89                         } else {
  90                                 contentLength = Int32.MaxValue;
  91                         }
  92                 }
  93
  94                 public WebConnectionStream (WebConnection cnc, HttpWebRequest request)
  95                 {
  96                         read_timeout = request.ReadWriteTimeout;
  97                         write_timeout = read_timeout;
  98                         isRead = false;
  99                         this.cnc = cnc;
 100                         this.request = request;
 101                         allowBuffering = request.InternalAllowBuffering;
 102                         sendChunked = request.SendChunked;
 103                         if (allowBuffering)
 104                                 writeBuffer = new MemoryStream ();
 105                         if (sendChunked)
 106                                 pending = new ManualResetEvent (true);
 107                 }
 108
 109                 bool IsNtlmAuth ()
 110                 {
 111                         bool isProxy = (request.Proxy != null && !request.Proxy.IsBypassed (request.Address));
 112                         string header_name = (isProxy) ? "Proxy-Authenticate" : "WWW-Authenticate";
 113                         string authHeader = cnc.Data.Headers [header_name];
 114                         return (authHeader != null && authHeader.IndexOf ("NTLM") != -1);
 115                 }
 116
 117                 internal void CheckResponseInBuffer ()
 118                 {
 119                         if (contentLength > 0 && (readBufferSize - readBufferOffset) >= contentLength) {
 120                                 if (!IsNtlmAuth ())
 121                                         ReadAll ();
 122                         }
 123                 }
 124
 125                 internal WebConnection Connection {
 126                         get { return cnc; }
 127                 }
 128 #if NET_2_0
 129                 public override bool CanTimeout {
 130                         get { return true; }
 131                 }
 132 #endif
 133
 134 #if NET_2_0
 135                 public override
 136 #endif
 137                 int ReadTimeout {
 138                         get {
 139                                 return read_timeout;
 140                         }
 141
 142                         set {
 143                                 if (value < -1)
 144                                         throw new ArgumentOutOfRangeException ("value");
 145                                 read_timeout = value;
 146                         }
 147                 }
 148
 149 #if NET_2_0
 150                 public override
 151 #endif
 152                 int WriteTimeout {
 153                         get {
 154                                 return write_timeout;
 155                         }
 156
 157                         set {
 158                                 if (value < -1)
 159                                         throw new ArgumentOutOfRangeException ("value");
 160                                 write_timeout = value;
 161                         }
 162                 }
 163
 164                 internal bool CompleteRequestWritten {
 165                         get { return complete_request_written; }
 166                 }
 167
 168                 internal bool SendChunked {
 169                         set { sendChunked = value; }
 170                 }
 171
 172                 internal byte [] ReadBuffer {
 173                         set { readBuffer = value; }
 174                 }
 175
 176                 internal int ReadBufferOffset {
 177                         set { readBufferOffset = value;}
 178                 }
 179
 180                 internal int ReadBufferSize {
 181                         set { readBufferSize = value; }
 182                 }
 183
 184                 internal byte[] WriteBuffer {
 185                         get { return writeBuffer.GetBuffer (); }
 186                 }
 187
 188                 internal int WriteBufferLength {
 189                         get { return writeBuffer != null ? (int) writeBuffer.Length : (-1); }
 190                 }
 191
 192                 internal void ForceCompletion ()
 193                 {
 194                         if (!nextReadCalled) {
 195                                 if (contentLength == Int32.MaxValue)
 196                                         contentLength = 0;
 197                                 nextReadCalled = true;
 198                                 cnc.NextRead ();
 199                         }
 200                 }
 201
 202                 internal void CheckComplete ()
 203                 {
 204                         bool nrc = nextReadCalled;
 205                         if (!nrc && readBufferSize - readBufferOffset == contentLength) {
 206                                 nextReadCalled = true;
 207                                 cnc.NextRead ();
 208                         }
 209                 }
 210
 211                 internal void ReadAll ()
 212                 {
 213                         if (!isRead || read_eof || totalRead >= contentLength || nextReadCalled) {
 214                                 if (isRead && !nextReadCalled) {
 215                                         nextReadCalled = true;
 216                                         cnc.NextRead ();
 217                                 }
 218                                 return;
 219                         }
 220
 221                         pending.WaitOne ();
 222                         lock (locker) {
 223                                 if (totalRead >= contentLength)
 224                                         return;
 225
 226                                 byte [] b = null;
 227                                 int diff = readBufferSize - readBufferOffset;
 228                                 int new_size;
 229
 230                                 if (contentLength == Int32.MaxValue) {
 231                                         MemoryStream ms = new MemoryStream ();
 232                                         byte [] buffer = null;
 233                                         if (readBuffer != null && diff > 0) {
 234                                                 ms.Write (readBuffer, readBufferOffset, diff);
 235                                                 if (readBufferSize >= 8192)
 236                                                         buffer = readBuffer;
 237                                         }
 238
 239                                         if (buffer == null)
 240                                                 buffer = new byte [8192];
 241
 242                                         int read;
 243                                         while ((read = cnc.Read (buffer, 0, buffer.Length)) != 0)
 244                                                 ms.Write (buffer, 0, read);
 245
 246                                         b = ms.GetBuffer ();
 247                                         new_size = (int) ms.Length;
 248                                         contentLength = new_size;
 249                                 } else {
 250                                         new_size = contentLength - totalRead;
 251                                         b = new byte [new_size];
 252                                         if (readBuffer != null && diff > 0) {
 253                                                 if (diff > new_size)
 254                                                         diff = new_size;
 255
 256                                                 Buffer.BlockCopy (readBuffer, readBufferOffset, b, 0, diff);
 257                                         }
 258
 259                                         int remaining = new_size - diff;
 260                                         int r = -1;
 261                                         while (remaining > 0 && r != 0) {
 262                                                 r = cnc.Read (b, diff, remaining);
 263                                                 remaining -= r;
 264                                                 diff += r;
 265                                         }
 266                                 }
 267
 268                                 readBuffer = b;
 269                                 readBufferOffset = 0;
 270                                 readBufferSize = new_size;
 271                                 totalRead = 0;
 272                                 nextReadCalled = true;
 273                         }
 274
 275                         cnc.NextRead ();
 276                 }
 277
 278                 void WriteCallbackWrapper (IAsyncResult r)
 279                 {
 280                         WebAsyncResult result;
 281                         if (r.AsyncState != null) {
 282                                 result = (WebAsyncResult) r.AsyncState;
 283                                 result.InnerAsyncResult = r;
 284                                 result.DoCallback ();
 285                         } else {
 286                                 EndWrite (r);
 287                         }
 288                 }
 289
 290                 void ReadCallbackWrapper (IAsyncResult r)
 291                 {
 292                         WebAsyncResult result;
 293                         if (r.AsyncState != null) {
 294                                 result = (WebAsyncResult) r.AsyncState;
 295                                 result.InnerAsyncResult = r;
 296                                 result.DoCallback ();
 297                         } else {
 298                                 EndRead (r);
 299                         }
 300                 }
 301
 302                 public override int Read (byte [] buffer, int offset, int size)
 303                 {
 304                         if (!isRead)
 305                                 throw new NotSupportedException ("this stream does not allow reading");
 306
 307                         if (totalRead >= contentLength)
 308                                 return 0;
 309
 310                         AsyncCallback cb = new AsyncCallback (ReadCallbackWrapper);
 311                         WebAsyncResult res = (WebAsyncResult) BeginRead (buffer, offset, size, cb, null);
 312                         if (!res.IsCompleted && !res.WaitUntilComplete (ReadTimeout, false)) {
 313                                 nextReadCalled = true;
 314                                 cnc.Close (true);
 315                                 throw new WebException ("The operation has timed out.", WebExceptionStatus.Timeout);
 316                         }
 317
 318                         return EndRead (res);
 319                 }
 320
 321                 public override IAsyncResult BeginRead (byte [] buffer, int offset, int size,
 322                                                         AsyncCallback cb, object state)
 323                 {
 324                         if (!isRead)
 325                                 throw new NotSupportedException ("this stream does not allow reading");
 326
 327                         if (buffer == null)
 328                                 throw new ArgumentNullException ("buffer");
 329
 330                         int length = buffer.Length;
 331                         if (size < 0 || offset < 0 || length < offset || length - offset < size)
 332                                 throw new ArgumentOutOfRangeException ();
 333
 334                         lock (locker) {
 335                                 pendingReads++;
 336                                 pending.Reset ();
 337                         }
 338
 339                         WebAsyncResult result = new WebAsyncResult (cb, state, buffer, offset, size);
 340                         if (totalRead >= contentLength) {
 341                                 result.SetCompleted (true, -1);
 342                                 result.DoCallback ();
 343                                 return result;
 344                         }
 345
 346                         int remaining = readBufferSize - readBufferOffset;
 347                         if (remaining > 0) {
 348                                 int copy = (remaining > size) ? size : remaining;
 349                                 Buffer.BlockCopy (readBuffer, readBufferOffset, buffer, offset, copy);
 350                                 readBufferOffset += copy;
 351                                 offset += copy;
 352                                 size -= copy;
 353                                 totalRead += copy;
 354                                 if (size == 0 || totalRead >= contentLength) {
 355                                         result.SetCompleted (true, copy);
 356                                         result.DoCallback ();
 357                                         return result;
 358                                 }
 359                                 result.NBytes = copy;
 360                         }
 361
 362                         if (cb != null)
 363                                 cb = new AsyncCallback (ReadCallbackWrapper);
 364
 365                         if (contentLength != Int32.MaxValue && contentLength - totalRead < size)
 366                                 size = contentLength - totalRead;
 367
 368                         if (!read_eof) {
 369                                 result.InnerAsyncResult = cnc.BeginRead (buffer, offset, size, cb, result);
 370                         } else {
 371                                 result.SetCompleted (true, result.NBytes);
 372                                 result.DoCallback ();
 373                         }
 374                         return result;
 375                 }
 376
 377                 public override int EndRead (IAsyncResult r)
 378                 {
 379                         WebAsyncResult result = (WebAsyncResult) r;
 380                         if (result.EndCalled) {
 381                                 int xx = result.NBytes;
 382                                 return (xx >= 0) ? xx : 0;
 383                         }
 384
 385                         result.EndCalled = true;
 386
 387                         if (!result.IsCompleted) {
 388                                 int nbytes = -1;
 389                                 try {
 390                                         nbytes = cnc.EndRead (result);
 391                                 } catch (Exception exc) {
 392                                         lock (locker) {
 393                                                 pendingReads--;
 394                                                 if (pendingReads == 0)
 395                                                         pending.Set ();
 396                                         }
 397
 398                                         nextReadCalled = true;
 399                                         cnc.Close (true);
 400                                         result.SetCompleted (false, exc);
 401                                         throw;
 402                                 }
 403
 404                                 if (nbytes < 0) {
 405                                         nbytes = 0;
 406                                         read_eof = true;
 407                                 }
 408
 409                                 totalRead += nbytes;
 410                                 result.SetCompleted (false, nbytes + result.NBytes);
 411                                 result.DoCallback ();
 412                                 if (nbytes == 0)
 413                                         contentLength = totalRead;
 414                         }
 415
 416                         lock (locker) {
 417                                 pendingReads--;
 418                                 if (pendingReads == 0)
 419                                         pending.Set ();
 420                         }
 421
 422                         if (totalRead >= contentLength && !nextReadCalled)
 423                                 ReadAll ();
 424
 425                         int nb = result.NBytes;
 426                         return (nb >= 0) ? nb : 0;
 427                 }
 428
 429                 public override IAsyncResult BeginWrite (byte [] buffer, int offset, int size,
 430                                                         AsyncCallback cb, object state)
 431                 {
 432                         if (isRead)
 433                                 throw new NotSupportedException ("this stream does not allow writing");
 434
 435                         if (buffer == null)
 436                                 throw new ArgumentNullException ("buffer");
 437
 438                         int length = buffer.Length;
 439                         if (size < 0 || offset < 0 || length < offset || length - offset < size)
 440                                 throw new ArgumentOutOfRangeException ();
 441
 442                         if (sendChunked) {
 443                                 lock (locker) {
 444                                         pendingWrites++;
 445                                         pending.Reset ();
 446                                 }
 447                         }
 448
 449                         WebAsyncResult result = new WebAsyncResult (cb, state);
 450                         if (!sendChunked)
 451                                 CheckWriteOverflow (request.ContentLength, totalWritten, size);
 452                         if (allowBuffering) {
 453                                 writeBuffer.Write (buffer, offset, size);
 454                                 totalWritten += size;
 455                                 if (!sendChunked) {
 456                                         result.SetCompleted (true, 0);
 457                                         result.DoCallback ();
 458                                         return result;
 459                                 }
 460                         }
 461
 462                         AsyncCallback callback = null;
 463                         if (cb != null)
 464                                 callback = new AsyncCallback (WriteCallbackWrapper);
 465
 466                         if (sendChunked) {
 467                                 WriteRequest ();
 468
 469                                 string cSize = String.Format ("{0:X}\r\n", size);
 470                                 byte [] head = Encoding.ASCII.GetBytes (cSize);
 471                                 int chunkSize = 2 + size + head.Length;
 472                                 byte [] newBuffer = new byte [chunkSize];
 473                                 Buffer.BlockCopy (head, 0, newBuffer, 0, head.Length);
 474                                 Buffer.BlockCopy (buffer, offset, newBuffer, head.Length, size);
 475                                 Buffer.BlockCopy (crlf, 0, newBuffer, head.Length + size, crlf.Length);
 476
 477                                 buffer = newBuffer;
 478                                 offset = 0;
 479                                 size = chunkSize;
 480                         }
 481
 482                         result.InnerAsyncResult = cnc.BeginWrite (buffer, offset, size, callback, result);
 483                         totalWritten += size;
 484                         return result;
 485                 }
 486
 487                 static void CheckWriteOverflow (long contentLength, long totalWritten, long size)
 488                 {
 489                         if (contentLength == -1)
 490                                 return;
 491
 492                         long avail = contentLength - totalWritten;
 493                         if (size > avail)
 494                                 throw new ProtocolViolationException (
 495                                         "The number of bytes to be written is greater than " +
 496                                         "the specified ContentLength.");
 497                 }
 498
 499                 public override void EndWrite (IAsyncResult r)
 500                 {
 501                         if (r == null)
 502                                 throw new ArgumentNullException ("r");
 503
 504                         WebAsyncResult result = r as WebAsyncResult;
 505                         if (result == null)
 506                                 throw new ArgumentException ("Invalid IAsyncResult");
 507
 508                         if (result.EndCalled)
 509                                 return;
 510
 511                         result.EndCalled = true;
 512
 513                         if (allowBuffering && !sendChunked)
 514                                 return;
 515
 516                         if (result.GotException)
 517                                 throw result.Exception;
 518
 519                         try {
 520                                 cnc.EndWrite (result.InnerAsyncResult);
 521                                 result.SetCompleted (false, 0);
 522                         } catch (Exception e) {
 523                                 result.SetCompleted (false, e);
 524                         }
 525
 526                         if (sendChunked) {
 527                                 lock (locker) {
 528                                         pendingWrites--;
 529                                         if (pendingWrites == 0)
 530                                                 pending.Set ();
 531                                 }
 532                         }
 533                 }
 534
 535                 public override void Write (byte [] buffer, int offset, int size)
 536                 {
 537                         if (isRead)
 538                                 throw new NotSupportedException ("This stream does not allow writing");
 539
 540                         AsyncCallback cb = new AsyncCallback (WriteCallbackWrapper);
 541                         WebAsyncResult res = (WebAsyncResult) BeginWrite (buffer, offset, size, cb, null);
 542                         if (!res.IsCompleted && !res.WaitUntilComplete (WriteTimeout, false)) {
 543                                 nextReadCalled = true;
 544                                 cnc.Close (true);
 545                                 throw new IOException ("Write timed out.");
 546                         }
 547
 548                         EndWrite (res);
 549                 }
 550
 551                 public override void Flush ()
 552                 {
 553                 }
 554
 555                 internal void SetHeaders (byte [] buffer, int offset, int size)
 556                 {
 557                         if (headersSent)
 558                                 return;
 559
 560                         if (!allowBuffering || sendChunked) {
 561                                 headersSent = true;
 562                                 if (!cnc.Connected)
 563                                         throw new WebException ("Not connected", null, WebExceptionStatus.SendFailure, null);
 564
 565
 566                                 if (!cnc.Write (buffer, offset, size))
 567                                         throw new WebException ("Error writing request.", null, WebExceptionStatus.SendFailure, null);
 568
 569                                 if (!initRead) {
 570                                         initRead = true;
 571                                         WebConnection.InitRead (cnc);
 572                                 }
 573                         } else {
 574                                 headers = new byte [size];
 575                                 Buffer.BlockCopy (buffer, offset, headers, 0, size);
 576                         }
 577                 }
 578
 579                 internal bool RequestWritten {
 580                         get { return requestWritten; }
 581                 }
 582
 583                 internal void WriteRequest ()
 584                 {
 585                         if (requestWritten)
 586                                 return;
 587
 588                         if (sendChunked) {
 589                                 request.SendRequestHeaders ();
 590                                 requestWritten = true;
 591                                 return;
 592                         }
 593
 594                         if (!allowBuffering || writeBuffer == null)
 595                                 return;
 596
 597                         byte [] bytes = writeBuffer.GetBuffer ();
 598                         int length = (int) writeBuffer.Length;
 599                         if (request.ContentLength != -1 && request.ContentLength < length) {
 600                                 throw new WebException ("Specified Content-Length is less than the number of bytes to write", null,
 601                                                         WebExceptionStatus.ServerProtocolViolation, null);
 602                         }
 603
 604                         request.InternalContentLength = length;
 605                         request.SendRequestHeaders ();
 606                         requestWritten = true;
 607
 608                         //
 609                         // For small requests, make a copy, it will reduce the traffic, for large
 610                         // requests, the NoDelay bit on the socket should take effect (set in WebConnection).
 611                         //
 612                         if (headers.Length + length < 8192){
 613                                 byte[] b = new byte [headers.Length + length];
 614
 615                                 Buffer.BlockCopy (headers, 0, b, 0, headers.Length);
 616                                 Buffer.BlockCopy (bytes, 0, b, headers.Length, length);
 617
 618                                 if (!cnc.Write (b, 0, b.Length))
 619                                         throw new WebException ("Error writing request.", null, WebExceptionStatus.SendFailure, null);
 620
 621                                 headersSent = true;
 622                                 complete_request_written = true;
 623
 624                                 if (!initRead) {
 625                                         initRead = true;
 626                                         WebConnection.InitRead (cnc);
 627                                 }
 628                         } else {
 629                                 if (!cnc.Write (headers, 0, headers.Length))
 630                                         throw new WebException ("Error writing request.", null, WebExceptionStatus.SendFailure, null);
 631
 632                                 headersSent = true;
 633                                 if (cnc.Data.StatusCode != 0 && cnc.Data.StatusCode != 100)
 634                                         return;
 635
 636                                 IAsyncResult result = null;
 637                                 if (length > 0)
 638                                         result = cnc.BeginWrite (bytes, 0, length, null, null);
 639
 640                                 if (!initRead) {
 641                                         initRead = true;
 642                                         WebConnection.InitRead (cnc);
 643                                 }
 644
 645                                 if (length > 0)
 646                                         complete_request_written = cnc.EndWrite (result);
 647                                 else
 648                                         complete_request_written = true;
 649                         }
 650                 }
 651
 652                 internal void InternalClose ()
 653                 {
 654                         disposed = true;
 655                 }
 656
 657                 internal void ForceCloseConnection ()
 658                 {
 659                         if (!disposed) {
 660                                 disposed = true;
 661                                 cnc.Close (true);
 662                         }
 663                 }
 664
 665                 public override void Close ()
 666                 {
 667                         if (sendChunked) {
 668                                 pending.WaitOne ();
 669                                 byte [] chunk = Encoding.ASCII.GetBytes ("0\r\n\r\n");
 670                                 cnc.Write (chunk, 0, chunk.Length);
 671                                 return;
 672                         }
 673
 674                         if (isRead) {
 675                                 if (!nextReadCalled) {
 676                                         CheckComplete ();
 677                                         // If we have not read all the contents
 678                                         if (!nextReadCalled) {
 679                                                 nextReadCalled = true;
 680                                                 cnc.Close (true);
 681                                         }
 682                                 }
 683                                 return;
 684                         } else if (!allowBuffering) {
 685                                 complete_request_written = true;
 686                                 if (!initRead) {
 687                                         initRead = true;
 688                                         WebConnection.InitRead (cnc);
 689                                 }
 690                                 return;
 691                         }
 692
 693                         if (disposed)
 694                                 return;
 695
 696                         long length = request.ContentLength;
 697
 698                         // writeBuffer could be null if KillBuffer was already called.
 699                         if (writeBuffer != null && length != -1 && length > writeBuffer.Length) {
 700                                 IOException io = new IOException ("Cannot close the stream until all bytes are written");
 701                                 nextReadCalled = true;
 702                                 cnc.Close (true);
 703                                 throw new WebException ("Request was cancelled.", io, WebExceptionStatus.RequestCanceled);
 704                         }
 705
 706                         WriteRequest ();
 707                         disposed = true;
 708                 }
 709
 710                 internal void KillBuffer ()
 711                 {
 712                         writeBuffer = null;
 713                 }
 714
 715                 public override long Seek (long a, SeekOrigin b)
 716                 {
 717                         throw new NotSupportedException ();
 718                 }
 719
 720                 public override void SetLength (long a)
 721                 {
 722                         throw new NotSupportedException ();
 723                 }
 724
 725                 public override bool CanSeek {
 726                         get { return false; }
 727                 }
 728
 729                 public override bool CanRead {
 730                         get { return isRead; }
 731                 }
 732
 733                 public override bool CanWrite {
 734                         get { return !isRead; }
 735                 }
 736
 737                 public override long Length {
 738                         get { throw new NotSupportedException (); }
 739                 }
 740
 741                 public override long Position {
 742                         get { throw new NotSupportedException (); }
 743                         set { throw new NotSupportedException (); }
 744                 }
 745         }
 746 }
 747